Riding gang reel mowers are known which comprise a self propelled traction frame that carries a seated operator who drives and guides the mower over a large turf surface that is to be mowed. Multiple reel cutting units are attached to the traction frame in a gang configuration for precision mowing of the grass on such a turf surface. In a typical gang configuration, the reel cutting units are disposed in a pair of rows with the cutting units in a first row being laterally spaced from one another. The cutting units in the second row would also be laterally spaced from one another, but would also be staggered and overlapped relative to the cutting units in the first row to cover and extend somewhat beyond the lateral gaps or spaces between the cutting units in the first row. This allows the reel mower to mow a relatively large and unbroken swath of grass in one pass of the reel mower over the turf surface. The Reelmaster 5010 Series mowers manufactured and sold by The Toro Company, the assignee of this invention, such as Toro's Reelmaster 5210 or 5410 mowers, are typical of such a riding gang reel mower.
Reel cutting units used on gang mowers customarily comprise a cutting unit frame having a pair of spaced side plates that are joined together by various cross members, such as a top wall and a back wall. A rotatable reel is located between the side plates and rotates about a horizontal axis to sweep uncut grass against a sharpened bedknife to cut the grass by shearing the grass between the blades of the reel and the bedknife. The reel cutting unit is typically supported for rolling on the ground as it cuts grass by long front and rear rollers that are rotatably journalled between the side plates of the cutting unit frame. The front roller is often grooved across its length such that it contacts the ground only at separated points of contact formed by the laterally spaced annular ribs that define the grooves on the roller. Such a grooved front roller is sometimes referred to as a Wiehle roller in the mowing art. The rear roller is usually provided with a smooth, solid outer surface along its length such that it contacts the ground substantially along its entire length.
In gang reel mowers of the type under consideration here, the grass in the turf surface is cut twice in the overlap areas between the front and rear cutting units and only once in the rest of the swath. In some turf conditions, this “double cut” in the overlap areas visually shows up in the cut grass in the swath as streaks of grass having a different color, usually a lighter color, than the grass in the rest of the swath. Such streaks are caused by a lower height of cut and/or damage to the grass leaf due to double cutting.
When this occurs, an observer usually sees as many streaks as there are overlap areas between the front and rear cutting units. In a typical fiveplex 3-2 gang configuration of cutting units arranged in a row of three front cutting units followed by two rear cutting units, there are four overlap areas. Thus, if the turf conditions are conducive for showing double cut marks, four usually lighter color streaks will be present within the cut grass swath along the overlap areas where the grass has been cut twice, first by the front cutting units and then by the overlapped portions of the rear cutting units.
These double cut marks or streaks can be objectionable to some operators of reel gang mowers to whom the aftercut appearance of the turf surface is particularly important. For example, owners of golf courses, particularly prestigious golf courses that host professional golf tournaments, desire that the cut grass swath provided by a mower in a single pass be as uniform in appearance from side to side as possible. In other words, such customers do not want to see streaks or marks of any type within the lateral width of the cut grass swath. At the very least, such customers want such streaks or marks to fade as quickly as possible.
One procedure known in the mowing art to eliminate or minimize double cut marks left by the overlapped reel cutting units in a gang reel mower is to change the type of grooved roller that is used as the front roller on the cutting units. Normally, as described earlier, the grooved front roller on a reel cutting unit is grooved across substantially its entire length, including being grooved in the overlap areas. If the turf conditions are conducive for showing double cut marks in the cut grass swath, this normal grooved roller has in the past been replaced with a grooved roller in which the outermost grooves on either end of the roller have been filled in or replaced by a side shoulder provided at either end of the roller in the overlap area. The side shoulders of such known grooved rollers have typically had the same outer diameter (OD) as the OD of the normal grooved roller (i.e. 3″) without shoulders. However, the OD of the remaining grooved portion of this roller has typically been slightly reduced (i.e. 2.9″) so that the shoulders have a slightly larger 3″ OD than the 2.9″ OD of the grooved portion of the roller extending between the shoulders. Such grooved rollers with side shoulders are then used as the front roller on each of the reel cutting units in the gang configuration, i.e. namely on all of the front cutting units and on all of the rear cutting units.
The solution described above can help minimize double cut marks since the use of shoulders on the front rollers of the cutting units in the overlap areas makes the cut less aggressive in the overlap areas, thus compensating somewhat for the fact that the grass is cut twice in such areas rather than once. However, the Applicants have discovered that the side shoulders on the laterally outermost sides of the front rollers of the two left and right front cutting units in the 3-2 gang configuration described above also make the cut less aggressive in strips along the extreme side edges of the cut grass swath. Thus, the Applicants have discovered that the solution previously used for helping minimize double cut marks leads to a new problem in the appearance of the cut grass swath. While it is true that the four double cut streaks in the interior of the cut grass swath may now be gone or greatly diminished, there are two new streaks or marks along each side of the cut grass swath where the grass has been cut less aggressively by the left and right front cutting units than in areas immediately to the inside thereof.
A similar problem to the double cut marks left in the interior of the cut grass swath is that of “double roll” marks that can also occur in the overlap areas between the front and rear reel cutting units due to the action of the substantially smooth rolling surfaces of the rear rollers on the front and rear cutting units. Double roll marks are streaks or marks having a different appearance than the rest of the cut grass swath and they may be lighter or darker than the rest of the cut grass swath depending on the grass type and turf conditions. In the 3-2 gang configuration described above, the solid rear rollers of the front and rear cutting units have rolling surfaces that also overlap with one another. Thus, the grass that is cut by these cutting units is rolled twice by the rear rollers in the overlap areas, first by one end of the rear roller of any given front cutting unit and then by the overlapped end of the rear roller of the trailing rear cutting unit. This double rolling in the overlap areas differs from the rest of the cut grass swath where the grass is rolled only once by a rear roller, thereby giving rise to a difference in appearance in the overlap areas.
A prior solution known in the art to address the problem of double roll marks is to use a shorter rear roller on all front and rear cutting units of the gang reel mower. In fact, the rear roller so used is sufficiently short so that there are no overlap areas between the ends of the rear rollers. The ends of the shorter rear rollers in the interior of the cut grass swath now effectively laterally align with one another rather than laterally overlap one another. Thus, the rear rollers on the cutting units do not roll the grass twice any longer in the overlap areas but only once, thereby preventing or mitigating the appearance of double roll marks in the overlap areas between the front and rear cutting units.
Again, the Applicants have discovered that this known solution to double roll marks creates new problems. The Applicants have recognized that the front cutting units are placed out front on the traction frame ahead of the front drive wheels of the reel mower. The Applicants have further recognized that equipping such front cutting units with shorter rear rollers detracts from their ground following ability and makes the front cutting units less able to stably follow highly contoured and undulating terrain, even though the rear rollers on a mower where the rear cutting units overlap the front cutting units by 2.5″ on each side are only 5″ shorter than before. Also, since the ends of the shorter rear roller on the front cutting units in this solution do not roll down the grass in the overlap areas; this grass tends to stands up taller and can be cut lower by the rear cutting units, thus leading to a worse double cut mark. Thus, front cutting units equipped with shorter rear rollers have been observed by the Applicants as having a decreased quality of cut compared to what they previously provided with longer rear rollers. Solving the double roll mark problem by equipping all the cutting units of a gang reel mower with shorter rear rollers thus gives rise to these new problems.
In addition, the Applicants have further recognized that the use of shorter rear rollers on all the cutting units of a gang reel mower further means that the extreme side edges of the cut grass swath are not rolled at all by any rear roller. Thus, as was the case when the prior art known solution to the problem of double cut marks was adopted, the grass along the sides edges of the swath is treated differently from the rest of the swath—it is not rolled even once. Thus, the known solution to double roll marks, while perhaps effective in removing double roll marks from the interior of the swath, is to cause a difference in appearance along the extreme side edges of the swath. This is a new disadvantage since it detracts from what many customers desire, namely a cut grass swath that has a uniform appearance all the way from one side edge to the other.